As military systems developers have increasingly improved precision of weapons and surveillance systems, the use of pulsed energy or radiation sources has been a key component in achieving improved precision. Generally speaking, pulsed radiation sources include lasers that operate with a given pulse rate and pulse width. Different pulsed radiation sources use different pulse rates and pulse widths.
Military personnel, whether acting offensively or defensively, utilize sensing equipment to assist with offensive and defensive military operations. From an offensive perspective, one operation for which military personnel use sensing equipment is to monitor targets that are being targeted by remote pulsed radiation sources to ensure the correct target is being illuminated. Targets are generally illuminated by pulsed radiation sources either by the weapons system itself or personnel on the ground for the weapons system to target. From a defensive perspective, one operation for which military personnel use sensing equipment is to detect pulsed radiation sources from potential enemy weapons, thereby providing military personnel to take preemptive action.
With regard to FIG. 1, a military field environment 100 shows field personnel 102 using a camera 104 for viewing a scene 106 in which military equipment 108a and 108b (collectively 108) being targeted by a helicopter 110 using a pulsed radiation source, such as a laser, to track and provide guidance for a weapons system. Typical pulsed radiation sources have a very short duty cycle relative to their pulse rate. For example, a laser or LED with less than one microsecond (μs) pulse width and pulse repetition frequency of 15 Hz may be typical of a pulsed radiation source.
Historically, cameras used to detect pulsed radiation sources have used a single sensor that is separate from the imaging sensor system. The single sensors are generally avalanche photo diodes (AVP) or pin diodes, which are analog sensors. The inclusion of a separate sensor from an imaging sensor results in increased camera weight and power consumption, both of which are valuable commodities for field personnel. The single sensor typically has a very narrow field-of-view, generally less than 1-degree, and is limited to detecting one laser at a time. In addition, the single sensor that needs to be boresighted or otherwise calibrated to the imaging system of the camera. Using a camera with the single sensor to detect pulsed radiation sources results in these problems and other operational limitations for field and other military personnel.